A press and a method for hard-cutting has become known from DE 10 2005 045 454 B4 in which at least one spacer forming a solid stop for the press movement is provided in a press tool. The press operates with upper and lower tools, each of which is driven by applying hydraulic pressure, which has the disadvantage that the upper and lower tools have to be supplied by different oil circuits.
In another configuration of this printed matter, the force generators for generating the pressing force of the upper and lower tools are formed by mechanical spring elements. However, an active press tool is not provided in this manner. These press tools only operate passively, namely according to the stroke between the press ram and the press table.
Accordingly, the mentioned spring elements are formed to be passive, that is, they are uncontrolled and generate only a certain pressing force, and no controller is shown and it is not shown how the pressing force is controlled in order to achieve a certain control or feedback control of the press tools.
Another press has become known through DE 199 08 603 C1, which achieves cutting with constant cutting depth.
At the lower tool, the counter punch is supported with an ejector spring. The bottom punch also has an end stop in the lower tool; accordingly, the workpiece is cut against a fixed stop of the counter support in the lower tool.
Due to the uncontrolled ejector spring, the spring characteristics of which cannot be influenced, there is the disadvantage that upon opening the press, the ejector spring in the counter support pushes towards the downholder in the upper part of the tool and thus conveys the stamping scrap back again into the initially stamped blank.
Thus, there is no controlled motion of the power unit that preloads the counter support.
EP 0 131 770 A1 shows generally the principle of fine cutting using a V-ring plate which is punched into the workpiece by the downholder.
DD 293 752 A5 uses a spring pack in the region of the lower part of the tool; however, this is an uncontrolled force generator which is not capable of removing the stamping scrap from the work area of the press in a controlled manner.
In summary, the mentioned prior art can be divided into of presses that operate with hydraulic drive elements which have the disadvantage that laying out the hydraulic circuits and the associate valve involves significant effort with high costs.
The second part of the publications relates to presses that operate purely mechanically, in which, however, the press tools are driven hydraulically. This is apparent in particular from DE 10 2005 045 454 B4.